What do birds do when temperatures drop?

When a bird experiences falling temperatures on a winter day, it can prevent its body temperature from dropping. 

Most birds respond to the cold in similar ways, but the temperatures that trigger their behavioral and physiological responses vary widely. In general the bigger the bird the easier it is to cope with cold temperatures.

Some behaviors and physiological responses that help them conserve heat include: 

1. Tucking feet and legs into their breast feathers.
2. Fluffing their plumage. This traps air, creating an insulating layer.
3. Finding shelter. Birds use dense shrubs and tree cavities to conserve heat.
4. Increasing their metabolic rate, producing more body heat
5. Shivering (produces more metabolic heat)
6. Roosting closely together with other birds. (Up to ten bluebirds have been found to roost in the same tree cavity on cold nights)
7. Some birds like Black-capped Chickadees can 'lower their body temperature at night and enter regulated hypothermia, saving significant amounts of energy. 
8. In addition, 'many birds store food and have exceptional spatial memory to relocate it, even a month later.' (from the on-line resource, Birds of North America)

9. 

   Other interesting facts: 

• Generally birds need more food in cold weather. Small birds need relatively more food than larger ones, and they generally eat smaller items, so they are more likely to be affected by a blizzard. A small bird's survival may depend on how well it can conserve energy during a storm. A chickadee, for instance, will increase its feeding intensity during cold weather.
• In general larger birds cope with the cold better than smaller birds.
• Did you know that individuals of a species living in colder regions tend to be larger than individuals living in warmer areas!

• Torpor: Some birds (hummingbirds, swifts, and nighthawks and relatives) may enter a state of torpor at night or during cold weather. Their temperature drops and metabolic rates slow letting them conserve energy when food is not available.

Common Questions about Birds in Winter:

 

Should I feed birds in winter? Will this help them survive?

Bird feeding provides easy food for birds. This means they have to spend less energy  trying to find food and can conserve valuable energy. This is especially important when the temperatures fall. Feeding birds is also a wonderful way to get to know your birds better!  But, bird feeders can also be deadly.  Predators (cats, hawks, even dogs) can easily find birds at feeders, dirty feeders can spread disease, feeders can attract non-native, invasive species (house sparrows, and starlings for instance) which can be detrimental to native birds, and birds might fly away quickly and crash into nearby windows.

What can I do to make my bird feeders safe?  

Keep them clean, install them less than two feet away from windows (to minimize window crashes), keep cats indoors, and monitor your feeders.

Will birds suffer if feeders go empty in the winter?  

Not usually. In general birds have a variety of sources of food that they rely on in winter including other feeders and natural sources.

Which birds do better in the  winter?

In general larger birds cope with the cold better than smaller birds.

Smaller birds have to work harder to keep warm, they need relatively more food, and they generally eat smaller items, so they are more likely to be affected by the weather.Smaller birds also lose heat relatively quickly.

If birds need lots of energy from food, why do chickadees at my feeder take a seed, then fly away to a tree to eat it? Wouldn't it be better to just stay at the feeder to eat lots of food at once? 

Chickadees and other birds often take a sunflower seed from a bird feeder  to dense cover to eat it before returning to get another seed. Although it would seem to make sense to maximize  the number of seeds  eaten per  minute, they have to balance the danger of being exposed to predators to the advantage of getting more calories per minute.

Should I provide water in winter?

Birds conserve water in their bodies much better than mammals. They do need to drink, but they can get the water they need from melting icicles, puddles, and in severe cold, snow. Birds take ‘snow baths’ in winter to keep their feathers preened (this is especially

important when they fluff up their feathers to create an insulating layer). Birds will appreciate water, and it is fun to watch them at a bird bath, but it is not necessary.  Laura Erickson, science editor at the Cornell Lab of Ornithology, says that when the temperatures are severely cold providing warm water may be detrimental. She's heard of starlings bathing in warm water in severely cold weather that got their feathers coated in ice and and were unable to fly.
 
What do birds eat in harsh winters?
Birds that don't migrate must rely on  food sources such as berries, seeds, grains,

and fruits. They have to find many food sources. It would be too risky to depend on only one or two bird feeders, for example. Birds really only supplement their natural diets of seeds, berries, grains and fruit  with the food they can get at bird feeders. Many birds also cache food  in bark crevices, knotholes, and pine needle clusters in the fall. Research shows that some birds such as chickadees develop new brain cells to help them remember and recover their cached food!

Does feeding birds affect migration?  

No. Bird migration is triggered by changes in day length not the availability of food. 

 
A piece of goose down seen through a microscope in Philip Linde's 2nd grade classroom in Newfield, NY. They chose this particular image for the challenge because they thought, with the lighting, that the barbs and barbules looked like twigs with an icy coating on a wintry day in Central New York.